Control apparatus



Feb.l l5, 1944. H, s, BEAKES y l 2,342,034- I GONTRQL'APYARATUS l Filed .April s, 1942 4 sheets-sheet 2 H25 AMBA/,W

Feb. l5, 1944.14 H.s. BEAKEs 2,342,034

- v Y CONTROL APPARATUS Fi'ed April 8, 1942 4 Sheets-Sheet 5 Hfs 4241103112? 4 Feb. 1s, 1944.

H. s. ABi'EAKEs CONTROL APPARATUS :Filed AApril e! 1942y 4 sheets-sheet l4 Patented Feb. 15, 1944 UNITED STATES PATENT OFFICE 2,342,034

CONTROL APPARATUS Howards. Beakes, Wilkinsburg, Pa., assignor to The Unionv Switch & Signal Company, Swissvale,` Pa., a corporation of Pennsylvania Application April'8, 1942, Serial No. 4384,129

' s claims. (01.246-420) v My invention relates tocontrol apparatus, and Ait has particular reference to the provision of novel and improved control apparatus and to the organization of such apparatus into novel and inrproved control systems of the class arranged for `use in connectionlwith a rstretch of railroad to detect obstructions falling or sliding onto the right-of-Way of the railroad. A

It has been proposed heretofore to provide slide detector fences along rthe right-of-Ways of railroads at locations Where obstructions to the rightoi-ways are likely to occur Vduet'o'land or snow slides, ,falling rocks ortrees, or the like. These fences are `made up of one or more' units, each comprising a pair offence sections which extend in opposite directions from a mid point and which are anchored at their [respective remote ends, and a circuit controller operatively connected with the adjacent free ends of the fence sections and arranged to govern signals controlling trac on the railroad. v`In such systems, latch or trip type controllers usually are employed and the parts are adjustedv so that theience sections are nor'- mally stretched tight but that whenever either fence section is 'struck by a falling object of sufcient size to cause a dangerous condition to exist should theobject lodge on the right-of-way, the section will deflect to trip oli orjoperate the contacts of the associated controller. In order to adjust the apparatus, it is customary toprovide suitable means, such as turnbuckles, for increasing or decreasing the tension to obtain the desired degree of tightness in the fence sections. This, of course, requires considerable attention from maintainers in orderto compensate the fences for the various ranges of ambient temperature conditions, since with the length of fencesections employed,'often reaching 400 feet or more, Lconsiderable expansion and contraction in the fence sections occur due to changes in ambient temperature. The compensation made available 'by the use of turnbuckles is ofcourse limited in 4scope to be eiiective 'in a small range of temperatures and does not provide means forautomatically compensating for relatively wide variations `in temperature. For example, a section adjusted to obtain the proper tension when the ambient temperature is high, as fduring a hot autumn day, might be caused during 'a succeeding'cold night to contract enough to trip oif the circuit controller. -On the other hand, a fencev section ad'- justed to the proper tension when the ambient temperaturel is low might be caused due vto a sudden rise in the `ambient temperature 'to expand to an extent sufficient to make the fence vslack `View showing in more detail controller represented in Fig.

and thuspermit the passage of obstructions Without tripping on the controuer. f

vIn View 'ofthe above-mentioned and other Vimportant considerations, it is anr object of" myV invention to provide novel and improved systems for detecting obstructions falling or sliding onto a right-of-way, arranged to be automatically compensated for changes in ambient temperature.

Another object is to provide novel andi-mproved slide detector fence systems arranged to avoid false operations of the systems due to variations in ambient temperature.`

A further object is to provide novel and improved forms of circuit controllers designed to compensate automatically for changes in ambient temperature when incorporated linto slide detector Afence systems.

A n additional object is to incorporatepairs of fence sections and the associated circuit controllers into fence units arranged tovcompensate for expansion' and contraction in the fencesections caused by changes in ambient temperature. Another 'object is to provide novel and improved forms Vof circuit controllers vparticularly Well adapted for use in slide detector fence {systems.

Another object is to provide novel' and improved forms of slide detector' fence systems.'

"The above-mentioned and other important objects and characteristic'features which willV become readily apparent from the 4iollovving description, are attained in accordance'with my inventio-nby employing a pair of fence .sections each having its free end operatively connected with a circuit co-ntroller and arranged to effect an operation of 'the-controller When and only 'When one of the sections is stressed by aforce exerted thereon not balanced by a force of substantially equal magnitude exerted on the other section.

I shall describe several forms of apparatus embodying my invention, and shall then point, out the novel `features thereof in claims.

In the accompanying drawings, Fig. 1 is a dia'- grammatic view showinga slide detector fence system embodying my invention.v Fig. 2 lis an isometricview showing onan enlarged scale one form of an improved circuit controller embodying my vinvention and adapted for use in the system represented in Fig. 1. Fig. 2a is a side sectional a portion of the 2. Fig. 3 is an isometric -view Ishovving a modified form of the circuit controller represented in Fig. 2, and also lembodying my invention.v Fig. 4 is a `front elevadetector fence systems, and also embodying my' invention. Figs. 9, 10, 11 and 12 are diagrammatic views illustrating another form ofv circuit controller embodying my invention. In each of the several views, similar reference characters have been employed to designate corresponding parts.

Referring to Fig. tem of the class employed along the' right-ofway of a railroad at locations such as at cuts, at the bases of rocky slopes, or any other locations where an obstruction to the right-of-way is likely toi occur due to sliding or falling objects, is represented as comprising a pair of fence sections B and :C and an associated circuit controller D. The 'fence sections are preferably of substantially equal lengths and each comprises a span of wire Iywhich spans extend in opposite directions from the location of the controller. Each span is supported by end posts 2 and as many intermediate posts 3 and 4 as the length of the span makes desirable or necessary. The end posts 2 are securely anchored, as by imbedding their lower ends in concrete foundations, and if desired auxiliary posts 6 may be utilized as shown for bracing such end posts. The intermediate posts 3 and 4 may be maintained upright by being imbedded either'in concrete, as in the case of posts 3, or in earth as is the case of posts 4.

Each span of wire I is rigidly fastened or anchored to the associated end post 2, and is slidably secured to each of the intermediate posts `3 and 4 in such manner as to be free to move longitudinally with respect to these posts. Each span extends a short distance past its associated post3 and is secured to a tension bar 1. The two tension bars 1 are spaced apart as shown and .are connected together through tensioning means, each preferably including a coupling member 8,

a spring 3, and a turnbuckle I for increasing or decreasing the tension in the associated spring `9. The parts are proportioned and turnbuckles I0 are so adjusted as to cause the two spans of wire to be stretched tight, but whenever either vsection of fence is struck by a falling objectv having a, size sufficient to create a dangerous condition should the object lodge upon the associated right-of-way, the fence section will deiiect and cause its associated tension bar 1 to move toward i-ts associated post 3. y

Each tension bar 1 is operatively connected with circuit controller D mounted on an upright post .I2 secured to a rigid foundation I3 at a location `intermediate the two tensionbars. Cir- ,cuit controller D may take different forms, one of which is represented in Fig. 2 as comprising .a suitable housing I5 provided at its forward side with a hinged cover I6 through which access to the Aoperating parts of the controller may be ob- .tained for adjustment or repair of the parts.

Housing I5 is provided in its opposite sidewalls *with guideways which slidably receive two operating members or plungers Ia and I8b operatively connectedI one with each tension bar 1,'re-

1, a slide detector fence systion of the drawings.

, plunger members are operatively connected with y contact operating means for causing operation of spectively, in such manner that a longitudinal movement of either bar 1, caused by a lateral displacement of its associated fence section, will cause a corresponding longitudinal movement of the associated plunger I8a or I 8b, as the case may be.

The plunger members I8a and IBb are arranged in parallel relation and hence aredisposed out of axial alignment and "are spaced apart lfor operation in a plane defined by the longitudinal axes of such members, as can be seen from an inspec- The free ends of the an associated Aset of contacts whenever either plunger member is caused to move due to a lateral deflection of its associated fence section. Various different forms of contact operating means may be operatively connected with the plunger members IBa and I8b, and one such form is represented in Fig. -2 as comprising an operating'block or cam basket 23 supported for longitudinal sliding movement in any suitable manner, as by providing projections 24 (see Fig. 2a) on the block cooperating with keyed channels 25 provided in the rear wall of housing I5.A Block-23 preferably has its upper face (as viewed in the drawings) slotted for receiving a connecting link 26 rotatably mounted on a pin or shaft 21 journaled in the slotted upperportion of the block. The two plunger members I 8a and I 8b have their free ends slotted for receiving one end orthe other of connecting link 2G, and each plunger member is provided with a pin 28 which cooperates with an open-ended slot 4provided in the associated end of the connecting link.

Block 23 further'comprises a supporting ledge 29 adapted to be engaged by a roller 30v provided on a contacty operating member 3l disposed for vertical movement and slidably mounted in a supporting arm 32 secured to the rear wall of housing I5. In the normal condition of the apparatus, as represented in Fig. 2, roller 30 `rides on and is supported by ledge 29, whereby member 3| is maintained in an upper position (as viewed in Fig. 2) against the bias of gravity and of a spring 33 vencircling member 3I and disposed between supporting arm 3'2 and a collar 34 provided .on member 3l. In the upper position of the contact operating member, a contacting' element 35 secured to but insulated from member 3 I, bridges va pair of contact iingers 35 suitably supported in housing I5. Other contact fingers 31 may be provided in'housing I5 and be disposed to be bridged will be made clear presently.

Circuit controller D and the slide detector fence ysystem as a whole operate in the following manner: Whenever either fence section is struck by a moving mass, such as by a slide or a large object like a tree or rock, the lateral pressure on the wire span forces the span to deflect laterally and move longitudinally through its loose fastenings by which it is supported by the intermediate posts 3 and 4. This longitudinal movement of a wire span is transmitted through the associated tension bar 1 to the plunger member I8a or I8b, as the case may be, associated therewith, and causes that member to move toward its associated post 3. For example, should a slide strike section C of Fig. l, plunger member I8b is caused by the resulting deflection of the fence section to move toward its associated post 3, or from left to right as viewed in the drawings. To a limited extent,

=the. :other plunger ima fmaylikewise .be :caused to 12move inthe .sameidire'ction Sdue i to 'the :i-forces :transmitted @through .the springs' 9 Afrom section C to the other section B. Theseorcesf'are, however,

largely iabsorbe'd in the .springs 49,?and the other -fence section B,-;being1anchored =atits remote end :and adjusted initially taut, is limited 1n expansion, hence. the 'distance through which plunger IBa operates is quite small `withirespect to 'the distance' through whichfthe other plunger oper- -fates. Connecting link 426 `will :therefore rotate :about an' axis 'throughI the upper pin 28 that connects .link 26 toplunge'r |8a,.and block 23 will be .moved to the right,itherebycausing ledge 29 to be .fmoved out of :supporting relation to roller 30.

Block 23 is `preferably so constructed (see Fig. 2)

as 'to :have la .slopingshoulde'r which will engage roller 3H after the ledge 29`aisremoved from supporting vrelation .to :the` roller, and such sloping shoulder will] exert a positive force `on the rollerlto drive contact "operating Zmember i3| from its normal to an .operated position,`.wththe result that contacts '3S1are noflongerbridgedand contacts 31 -become bridged. These contacts iio and 31 may be interposed, as is the usual custom, in the convtrol circuits of wayside signalsgoverning tralic on the'associated" stretch, and may be utilized to cause `such signals to display either caution or "stop, whichever.'iindicationiisdesired, until the obstruction "is removed/and the circuit controller is restoredto its 'normal condition 4:in a 'manner to be madeiclear presently.

It is,;offcourse, readily apparent that if fence lsection B is struckbya moving mass, the deflection of that.' section willcause plunger |861. to move V3;

.from right-to left, and will cause block 23 to move also to the Vleft toA remove ledge 2S fromasupportingv relatio-ntorol-ler 3U, and vto bring a shoulder formed on block S23 finto engagement withroller vv3|), whereuponcontact'operating member-3| will. .'-be vcaused to-fass'ume Aits operated position. The

contacts of controller Dare, therefore'caused to operate whenever either fence section is caused to deflectby a forcenotsubstantially balanced by .a force of .equal magnitude exertedon the other section. l

The-.slide detector `fence vsystem, incorporating controller D, is arranged to be self-compensating for variations in ambient temperature. That is fto say, whenever there `is 'an :expansion or con- :traction ofil the fencersections, the Etension bars 1 .arewca-used to move `away `from Aor toward their yassociated posts .3, respectively; Since the'wire spans .of eachsection are ofsubstantially equal lengths, any variation of the ambient'temperature that mightfcause lexpansion orcontracnecting link 25 is caused to rotate about-anl axis through itspivot 21 but is not caused to have translatory motion. Block. 23 accordingly vis caused to remain substantially unmoved, .and ledge -29,likewise is unactuated so that AContact operating-member 3| retains its contacting mem'- 5 plunger members.

suchas a plugA receptacle '411 secured to a support.

oef csfimbneging reiaueniwith contacts es. contacts` of icontro'ller LDware, Ltherefore, :unactu- .ated-when plungenmembers MiaY and-.|817 move through. substantial-ly equal distances in opposite directions ldue .to ybalanced variations in the stresses fin the two-'fence sections.

.It .should :be notedthat "whenever operating *block "2'3 isscaused Yto .lmove `vitsv supporting ledge 29 :,outv'of .supporting-relation :to 'roller 30, contact @operating member 1-3| is then caused to operate xfromits .normal-to an operated ..position due to lea combination ..of =f.orces fexerted .'on the member. .These forces .comprise.(1)..gravity, (2) theiorce 'roi spring 35 :and (3) the force Aexerted `by the -shoulderxof block 23 on'iro1ler'3ll. This .lastforce may `not always come linto `action' but will .do Lso should the movement or member 3| be Arestricted or vdelayed :by friction ora binding ofthe parts,

hence this. ypositive force-down f feature insures iagainst fa failurefofmember'l to. drop. lThe *spring 'forceiof :spring- 35 will 'act to'move roller -30 :beyond mechanical contact vwith block 23, therebyx'isola'ting the'conta'ct structurezfrom Ythe operating portion and providing protection for thev -contact structures should a fence section) be ruptured, or' otherwise -be fcaused to operate its plunger mem-ber abruptly lback toitsinormal position.

A modification of the Contact operating means just `described "is illustrated in Fig. `3, wherein it-he `free ends of -the .plunger members" |811v and |8b :aremrov-ided with confrontingl and matching HracllsfZfll which rfare "engaged by a pinion gear i21| having its axle 22 journaled insuitable openings provided in the 'two side pieces `of a freely movable yoke member YI which encloses the ends of the Suitable contacting means.

and a cooperating plug f4l, are operatively connected with yoke 'YI as by means of a chain or yrope `42 `fastened to plug 4| and then looped over `a pulley '43. The twofends ofthe chain are sevcured vto yoke Y| so thata longitudinal movement yof the yoke in either direction will withdraw plug 44| from 'engagement with receptacle 4E).

Whenever either 'plunger member Ita or |81) `is 'caused tofmovelongit'udinally dueto a lateral deflection lof its associated fence section, gear 2| vis caused to rotate andmove in the same Vdirection as that of the operated plunger member, whereupon yoke Y| also moves in thesame direction to Vdisconnect 'plug 4| Yfrom receptacle 40. Should,

however, the two plunger members move in opposite directions for substantially equal distances,

gear 2| will then rotate but yoke Y I` will not move longitudinallywith respect to receptacle 40, hence under such conditions, plug 4I will .not be actui-ated. The arrangement shown in Fig. 3 is, there- @rasch-compensating for variations inambient temperature. In addition, the parts areI arranged so asto avoidall possible injuries to the contact- 'ing members should a fence .section be ruptured, ror otherwise be caused to Aoperate itsplun'ger "member abruptly back toits normal position after anoperation thereofl due to a deflection ofa fence i section.

Another form of contact operating means is represented in Fig. 4, wherein freely movable yoke member YI enclosing 'and operatively connected with the free ends of plunger members |311 and |81) bythe engagement of vgear `2| with the racks V20 YVformed on the' plunger members, is provided withacammed surface having two opposing slop- -ing shoulders or-sideseither of which will operatively engage a contact operating plunger A4E slidf ably mounted in an openingv 41, disposed substanz shoulders.

tially atright'angles to the line of movement of lyoke YI, provided in a supporting member 48 Vsecured to housing I5. Plunger-46 is biased, as by a coil spring 49, into engagement with the cammed surface of member 45 of yoke YI, and as can best be seen in Fig. 5, has a laterally extending slot 50 for cooperating with a beveled or tapered locking dog I (see Fig. 6)` formed on or secured to a latch member 52. Latch member 52 is'slidably mounted (see Fig. 4) in axially aligned openings 53 and 54 provided in member 48 at right angles to opening 41, and is provided with'biasing means,

`such as a spring 51 bearing against a shoulder on member 52 and a surface of supporting member 48, for biasing dog 5I into engagement with plunger 46.

Plunger 46 normally occupies the position in which it is represented -in Fig. 4, and yoke YI normally is positioned as shown so as to have its cammed surface engaged by plunger 46 at a point "substantially midway between its sloping sides or In this condition of the apparatus, dog 5I of latch 52 is forced by spring 51 into engagement with the side of the plunger. When yoke YI is moved longitudinally due to a deflection of either fence section, one or the other of the two sloping shoulders of cam member 45 engages plunger 46 to depress it-to a position such thatA slot 5D and beveled dog 5I are inV alignment. 'The dog 5I accordingly is forced into slot 56 and due to its taper. forces the plunger down and causesit to be actuated out of engagement with the surface of cam 45.

The movement of plunger 46 is utilized to control contacts interposed in the control circuits of the associated wayside signal system. These contacts may be operatively connected with plunger 46 tol be opened or closed, as desired, when the plunger is caused to operate, or as shown, the contacts may be operated by the movement of latch member 52 resulting when plunger 46 is depressed. The particular contact arrangement shown is thus merely illustrative and comprises two contact ngers 55 and 56 suitably supported in housing I5 and biased into engagement with each other to form a circuit controlling Contact 55--56 when plunger 46 is in its normal position. When plunger 46 is depressed due to the longitudinal movement of cam 45, andis forced out of engagement with cam 45 by the action of tapered dog 5! on latch member 52, an insulated tip on member 52 engages contact finger 56 to operate it away from its cooperating finger' 55, thereby opening contact 55-56.

In the operated position of the circuit controllenplunger 46 is latched out of engagement with vyoke YI due to the keying' action of dog 5| in slot 56: As a result, therefore, the yoke member YI is free to move after operation of the contact has been effected, withoutv affecting in any manner either thevcontacts incorporated into the controller, orY the plunger 46 latched in its .operated position. vvIt follows that with plunger 46 latched out oi` engagement with yoke YI, and with the yoke free to move after having caused an operationof plunger 46, protection is afforded against possibility of damage to the apparatus .-should relatively large stresses be set up in a fence ing springs and other portions of the fencel system,'and will not be transmitted to plunger 46, hence there is no possibility of jamming, breaking or injuring the plunger andits cooperating latch member 52 and contacts.v

After an operation of the controller has been effected, the apparatus may be restored to its normay condition if the fence sections are in their respective normal positions, by manually operating latch member 52 against the force of its spring 55 to the position where tapered dog 5I clears slot 50 of plunger 46. The plunger 46ac cordingly is forced into engagement with yoke YI, and latch member 52 is caused to hold its tapered dog 5I in engagement with the side of plunger 46. In this condition ofthe apparatus, the control contacts are in their normal positions, and the circuit controller is in its normal condition as illustrated in Fig. 4.

A circuit controller arranged to incorporate the apparatus represented in Fig. 4 is of course self-compensating for ambient temperature variations, since opposing movements of the two rack` members I8a and I8b cause gear 2l to rotate but do not cause yoke YI to move' longitudinally with respect to plungerY 46, hence a contraction or an expansion of the two fence sections caused by a variation of the ambient temperature will not cause operation of plunger 46 and the contacts operatively associated therewith.

The contact operating means just described may be employed in'connection with'an actuating member 66 secured to each of the two tensioning bars 1 of the fence section. In such an arrangement, shown in Fig. '1, the cammed surface 45 is formed directly on or secured to operating member 60, which member preferably' has one of its two ends yieldingly connected to one and nonyieldingly connected to the other of the two'fence sections, while the other end of bar 66 is yieldingly connected to the other andnon-yieldingly connected to the one fence section, respectively. The remainder of the apparatus (not shown) of this form of controller may be of any of the forms shown respectively in Fig. 2, 3 or 4 as desired, and for the purpose of example the upper portion of plunger member 46 is represented in the drawings to indicate that this plunger, together with its associated latch member 52 and contacts operatively associated therewith and shown in detail in Fig. 4, may be employed to cooperate in the manner described heretofore to cause operation of plunger 46 and the associated contacts whenever operating member 66 is caused to move longitudinally in response to a deflection of either of theassociated two fence sections.

The circuit controller represented in Fig. '1 does not itself provide compensation for Iexpansion and contraction in the fence system due t0 ambient temperature changes, but if such compensation is desired, special arrangements of the two cooperating fence sectionsmay be employed. Typical ones of these special fence sections are represented in Figs. 8a, 8b, 8c and 81d, and in each Yof these arrangements the fence sections are operatively connected to the circuit' controller operating member 66 in such manner as to effect av 'the event that either one of the sections is stressed aandoen hencef theV resultant force'l isl substantially zeroLinmagnitude'V andi' noI longitudinal movemen-toi' the member-iscau'seditotake place.

The fence sections shown in- Figs'. 8a-8d1inc1u'- sive are, inr generali, operatively connected tooperating member 6`0f otcontroller` D through` two equalizer members 6 l?, one for each: fencesection. Eachmember 61 is connected. to' its .associated fence section through'a` non-yielding connection, is. connected to the other fence section through a yielding connection such asby afspring 62:, and the twov connecting membersare pivotallysecuredto opposite ends of the operating member '60.; In Fig. 8a, the yielding connection-of'` member El? to itsI associated section` is establishedl at theff-ree-end of the member, and the non-.yielding connection to the other fence section is established at a .point intermediate? theY twonen'ds. ot' 'thed member.. In Fig. 8b; the` positions' ofthe yielding. andlnontyielding connections are reversed; In` Fig. 8c', both the. yielding` and noneyielding connections' arev effectedv atthe free ends of the'wconnectine' members. In Fig; 8d, an. equalizer member. 63 pivotally secured at its` mid point'. tor-oneendl or operating member lill:y ofi the controller', has. one: ofi its' ends yieldingly connected'. toi-one. and 'nonyieldinglly connected. to the other fence section', and. has .its opposite: endy yieldingly' connected.` to` the other and. non-yieldinglyy connected to'wthe one fence section.

The arrangements of the fencelsections shown in` Figs.. Sai-8d arer all. characterized by theA fact. that when'. substantially equaland opposite forces are exerted bythe fence sectionson the equalizing members; a. resultant. force-1 of substantially. zero magnitude is. appliedto the operatingi mem.- ber- 60 ofthe. associatedcircuit. controller. The arrangements permit a limitedmovement ofthe' fence. spans to. take, place, thereby allowing leach span -to elongate or: shorten with chan-gesinzthe ambient. temperature.. These, changes. in span length vary thev tension'. in thezsprings 62 andthe forces exerted onzthea'ssociat'ed: connecting mem`t` ber, but being balanced; and. opposite inusense do: not cause a; longitudinal: movement of the associated circuit controller` operating member B0.' When, however, unbalanced forces; are exerted on the connecting members, as wheni onefence section is struck byr a` slide or moving object, then the resultant. force' causesv longitudinal movement of the associated :circuit controller operating member to cause in turn operation: of the.` asso-r ciated contacts. The fence. section arrangements shown in Figs. Sa-Sd may therefore.. be .employed in connection with anyv oneof the. circuit con'.- trollers represented respectively in Figs.;l 2,. 3, 4' and '7. The-fence. section' arrangements. have; however; particular utility in. connection; with a. controller of the type vrepresented in Fig.. 7,. and will cooperate therewith to provide.. such al com bination with. compensati-on for: ambient tem perature. variations; l

Another formof circuit controller embodyingv my inventionrepresented inEigsfQ, 10, 11 andi.12,. comprises an .equalizer barV lll` having itsone end yieldingly connected-toene section and non-yield ingly connected to` the other section, and having its other end yieldingly connected to the other section and rigidly connected -to the one section. Intermediate the ends of member 'l0 is secured a projecting actuating member 1| for cooperating with contact operating means comprising plunger 46 and associated latch member and contacts (not shown but similar, for example, in arrangement and construction to the plunger, latch rod section occur.

andi cooperating contacts represented in liis.v 4l. The actuating member 1 l; isoperativelyconnected with fiplungerzdl through the medium. of a; biture catedyckefmember l2. secured. to= a iackshaft 73 supponte'din bearings 15. mounted'. in. -a .casing on housing; 143,. enclosing 'equalizerbarz 10` and attached' to:y midpost; l2. into anotherf housing ori casing; 1B* in`v whichv are contained plungerfMy andits associated latch lrod andicontacts; and. also camY meansfor actuatingtlieplunger: These cam-.means comprise two Wing membersalland a cooperatingzbodymember: 7.8,. all" secured; tofy jackshaft 1:3. Body memberul' is.: provided, with. slotted openings. 'I9v ior permitting theswing orear.' members 1.1 tobel acl-.- justably secured by bolts 8G to thebody member; thereby'to provide means. for adjusting the spread ofthe members.. Thel tips` of members 'Il form actuating cam surfaces for: depressing.` or actuatingiplungerv 46, and the bodymember 'I8 mayas showntiormfa. portion oi the.- cammed surfacel for limiting theiupward. travel of plungerl 4B when the apparatus is in its normal condition.

. Thefxcircuit controller represented. inL Figsi 9, 10, 11 and 12 is in its normal condition, asshown; wheneverithe: stresses inthe twoy fence sections aref balanced; If, due to variations: in the ambient temperatur@ the sections contract, equalizer.- bar' luis caused. to` rotate. about its midpoint without eiecting. operation of yoke member l2, Shou1d;. however; afsiide. or object strike one of the sec.-I tions` and cause that section. to. deilect,` then equalizer bar is caused'to` pivot -about'its end that: iszeinelastically connected' to the otherfencesection', and thelateral movement of. the equalizer barfwiit cause yoke member. 1-2 to rotatey jack-- shaftr'l3--and bringv` one or. theV other of the' wing tips'. 'Il4 into Yengagement with plunger 46,. and thereby; will cause: thef'plunger to bedepressed. to a point such. that it is latchedV upv by its as sociatedl'atch member hereinbefore mentioned;

Bifurcated yoke member; 'l2 permits-factuating.' member ll touloe readilyv disengaged therefrom shoulda relativelylarge delectionUof the fence: When this.v happens, the'l yoke:v member m-ay be operatedout of. the path. ofv ac tuatingmember `l'rl by'meansof a spring. 82; (see- Fig.. 12) secured to housing '11B `and" bearing on a; cam shaped portion. 8l formed on or secured to:u jackshait 13;. Whenzshaft'lSisrotated tofapont; such that. actuating member'll disengages from: yoke lf2, spring 82.'then1bears.against the' side faces of. element Bi and. causes shaft 1.3 to continue: to rotate so as. to move both. legs` of the; yoke.4 out of ther path oi. member 'HL It follows thatshould anv extremely large object or. slide: strike the fence section' and` cause a'. relatively large'. deflection to. take place', actuating: member.

ll. will be. disengaged. fronr yoke 'l2 andthe; yoke will be moved out oi. the path of. member; TI. so'v that if a rupture occurs, in. the. fence section,vor' theobject passes. through. the-section andLipermitsi thelsection torebound abruptly backi t'oits nerfv ina-lposition, the actuating-member w-ill here stored'abruptly to its` normalposi-tion but will3 not' Strike, iam, orf injure tlfiexyoke'member'and:v its associated con-tact operating apparatus-1 From the foregoing description of the various forms of circuit controller and fence section arrangements, embodying my invention, it is readily apparent that such apparatus when organized into slide detector fence systems provides compensation for ambient temperature variations and hence functions to improve the operation of the systems by reducing the necessity of frequent The jackshaft 1.3iextends adjustments ofthe fence sections stresses, and also` by reducing the possibility of improper operation of the systems due to variations in the ambient temperature. It is, of course, apparent. that each of the diierent forms of circuit controllers shown in the drawings might be modied to incorporate features and structural arrangements shown in other forms .of the represented controllers. For ex-ample, the yokesYl of Figs. 3 and limay have associated therewith contact operating means `of the type shown in Fig. 2 and involving ledge 29, roller 30 and contact operatingmember 3l; while operating block 23 of Fig. 2 may likewise have associated therewith contact operating means of the type shown in Fig. 3 or Fig. 4.

.l Although I have herein shown and describe only a few forms. of control apparatus embodying my invention, it is understood that various changes and modications may be made therein within. the scope of the appended claims without departing from the spirit and scope of my invention, t ,v

vHavingrthus described my invention, what I claim is:

1. In a protective system for detecting obstructions falling or sliding onto the roadway of a railroad, of the class comprising a pair of fence sections extending along said roadway, each said section being anchored at one of its ends, and a circuit controller operatively connected to the free ends of .said fence sections and arranged to govern signals controlling traffic on the railroad, the .improvement consisting of the provision in such a system .of a circuit controller comprisingv a housing-two plunger membersone securedto the rfreeiend. vof each of said fence sections and slidably mounted respectively in opposite Walls of said` housing, an operating member slidably mountedA for longitudinal movement, a connecting link rotatably mounted on a shaft journaled insaid. operating member and operatively connected with each of said plunger members for rotation about either. of said members or said shaft according as only one or both of said plunger members moves longitudinally, and contacty operating means operatively connected with saidy operating member for operation in responsel to a longitudinal movement of said operating member effected by a rotation of said connecting linkv about eitherplunger member but not by a rotationl of said connecting link about said shaft.

2. vIn a protective Vsystem for detecting obstructions falling or sliding onto the roadway of a railroad, of the class comprising a pair of. fence sections extending along said roadway, each said section being anchored at one of its ends, and a circuit controller operatively connected tothe. free ends of said fence sections and arranged to govern signals controlling ,trac on the railroad, the improvement consisting of the provision in such a system of a circuit controller comprising a housing, two plungermembers slidably mounted inl opposite walls of said housing and secured tothe free end of each of said fence sections, respectively, an operating member mounted for sliding movement, a connecting link rotatably mounted on a shaft journaled in said operating member and operatively connected with each of said plunger membersv4 for effecting a movement of said operating member when either plunger member moves in either direction lbut not when both plunger members movein opposite directions, a gravity biased .member supported by said operating member, means forqforcing down said gravity biased member when said operating member is caused to move, and ,contactsA operativelyY connected with said gravtybiased member and operated when such member is forced down.

3. In combination, aA pairv of fence sections, a

circuit controller having a member for operating contacts in response to a longitudinalmovement of said member, two bars connected to the opposite ends of said member respectively, an extensible connection from onev of saidtwo fence,

sections to one of said two bars vanda non-extensible connection from said one fence section to the other of said two bars, and an extensible connection from the other of said two fence sections to said other bar and a non-extensible connection from said other fence section to-said one bar, said extensible and non-extensible connections to each bar being arranged so as to eilect` between the other of said fence sections and said.

other end of said bar and a non-extensible connection between said other fence section and said one end of said bar, said extensible and nonextensible connections being eective to produce a longitudinal movement of said member only in response to a lateral deflection of one but not both of said fence sections.

5. In a protective f ence for a way comprising a pair of fence sections extending along said way, each said fence section being anchored at one end and movable at the Vother end, said movable ends beingconnected together by yieldable means which maintains the sections stretched tight while allowing for expansion and contraction, the combination with said fence sections of va circuit controller including a longitudinally movable operating member and a contact operated in response to longitudinal movement of said operating member, and means connecting said operating member with the movable ends of said two fence sections and effective to produce longitudinal movement of said operating member to operate said circuit controller in response to longitudinal movement of either fence sectionnot' balanced by a substantially equal andopposite movement of the other fence section.

- HOWARD S. BEAKES. 

